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C-C chemokines released by lipopolysaccharide (LPS)-stimulated human macrophages suppress HIV-1 infection in both macrophages and T cells.

Verani A, Scarlatti G, Comar M, Tresoldi E, Polo S, Giacca M, Lusso P, Siccardi AG, Vercelli D - J. Exp. Med. (1997)

Bottom Line: A combination of recombinant C-C chemokines blocked HIV-1 infection as effectively as LPS.Here, we report an inhibitory effect of C-C chemokines on HIV replication in primary macrophages.Our results raise the possibility that monocytes may play a dual role in HIV infection: while representing a reservoir for the virus, they may contribute to the containment of the infection by releasing factors that suppress HIV replication not only in monocytes but also in T lymphocytes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Technological Research, San Raffaele Scientific Institute, Milan, Italy.

ABSTRACT
Human immunodeficiency virus-1 (HIV-1) expression in monocyte-derived macrophages (MDM) infected in vitro is known to be inhibited by lipopolysaccharide (LPS). However, the mechanisms are incompletely understood. We show here that HIV-1 suppression is mediated by soluble factors released by MDM stimulated with physiologically significant concentrations of LPS. LPS-conditioned supernatants from MDM inhibited HIV-1 replication in both MDM and T cells. Depletion of C-C chemokines (RANTES, MIP-1 alpha, and MIP-1 beta) neutralized the ability of LPS-conditioned supernatants to inhibit HIV-1 replication in MDM. A combination of recombinant C-C chemokines blocked HIV-1 infection as effectively as LPS. Here, we report an inhibitory effect of C-C chemokines on HIV replication in primary macrophages. Our results raise the possibility that monocytes may play a dual role in HIV infection: while representing a reservoir for the virus, they may contribute to the containment of the infection by releasing factors that suppress HIV replication not only in monocytes but also in T lymphocytes.

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LPS suppresses HIV-1 replication in MDM cultures infected  in vitro. MDM from healthy donors were infected with HIV-1Ba-L (A),  the primary NSI isolate HIV-15088 (B), or HIV-1IIIB (D), all at 500 pg/ml,  in the presence or absence of LPS (1 μg/ml). MDM were washed 1 d  later and further cultured, adding LPS every 3 d. Culture supernatants were  harvested daily, and tested for p24 Ag secretion by ELISA. The data are  representative of 10 (A), 3 (B), and 2 (D) separate experiments. In (C)  MDM were infected with HIV-1Ba-L or HIV-15088 in the presence of decreasing concentrations of LPS. p24 Ag secretion was assessed 5 d after infection.
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Figure 1: LPS suppresses HIV-1 replication in MDM cultures infected in vitro. MDM from healthy donors were infected with HIV-1Ba-L (A), the primary NSI isolate HIV-15088 (B), or HIV-1IIIB (D), all at 500 pg/ml, in the presence or absence of LPS (1 μg/ml). MDM were washed 1 d later and further cultured, adding LPS every 3 d. Culture supernatants were harvested daily, and tested for p24 Ag secretion by ELISA. The data are representative of 10 (A), 3 (B), and 2 (D) separate experiments. In (C) MDM were infected with HIV-1Ba-L or HIV-15088 in the presence of decreasing concentrations of LPS. p24 Ag secretion was assessed 5 d after infection.

Mentions: To characterize the effects of LPS on the replication of HIV-1 in monocytic cells, MDM from normal donors were infected in vitro with the monocytotropic HIV-1Ba-L strain, in the presence or absence of LPS (1 μg/ml). Fig. 1 A shows that p24 Ag secretion in untreated MDM cultures rapidly reached high levels, which were maintained for over 10 d. In contrast, p24 Ag secretion by LPStreated MDM remained extremely low throughout the culture time. RT activity in the same cultures showed a similar pattern (data not shown). Fig. 1 B shows that LPSdependent inhibition of p24 Ag secretion was also observed in MDM cultures infected in vitro with HIV-15088, a primary isolate from an asymptomatic HIV-1-infected patient with the biological characteristics of an NSI isolate. LPS had a potent inhibitory effect on the replication of both HIV-1Ba-L and HIV-15088. Fig. 1 C shows that p24 Ag secretion was inhibited by >70% using LPS at a concentration of 1 ng/ml. Notably, inhibition was still apparent when LPS was added at 10 pg/ml, a physiologically significant concentration (13). Interestingly, LPS addition did not inhibit HIV-1 expression in MDM cultures infected with the SI laboratory strain, HIV-1IIIB (Fig. 1 D). The surprisingly high levels of replication of our HIV-1IIIB in MDM are likely to result from multiple passages of the viral stock in human primary PBMC. Addition of LPS did not result in significant cell death, nor in apoptosis, as assessed by Trypan blue or propidium iodide staining (data not shown).


C-C chemokines released by lipopolysaccharide (LPS)-stimulated human macrophages suppress HIV-1 infection in both macrophages and T cells.

Verani A, Scarlatti G, Comar M, Tresoldi E, Polo S, Giacca M, Lusso P, Siccardi AG, Vercelli D - J. Exp. Med. (1997)

LPS suppresses HIV-1 replication in MDM cultures infected  in vitro. MDM from healthy donors were infected with HIV-1Ba-L (A),  the primary NSI isolate HIV-15088 (B), or HIV-1IIIB (D), all at 500 pg/ml,  in the presence or absence of LPS (1 μg/ml). MDM were washed 1 d  later and further cultured, adding LPS every 3 d. Culture supernatants were  harvested daily, and tested for p24 Ag secretion by ELISA. The data are  representative of 10 (A), 3 (B), and 2 (D) separate experiments. In (C)  MDM were infected with HIV-1Ba-L or HIV-15088 in the presence of decreasing concentrations of LPS. p24 Ag secretion was assessed 5 d after infection.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196157&req=5

Figure 1: LPS suppresses HIV-1 replication in MDM cultures infected in vitro. MDM from healthy donors were infected with HIV-1Ba-L (A), the primary NSI isolate HIV-15088 (B), or HIV-1IIIB (D), all at 500 pg/ml, in the presence or absence of LPS (1 μg/ml). MDM were washed 1 d later and further cultured, adding LPS every 3 d. Culture supernatants were harvested daily, and tested for p24 Ag secretion by ELISA. The data are representative of 10 (A), 3 (B), and 2 (D) separate experiments. In (C) MDM were infected with HIV-1Ba-L or HIV-15088 in the presence of decreasing concentrations of LPS. p24 Ag secretion was assessed 5 d after infection.
Mentions: To characterize the effects of LPS on the replication of HIV-1 in monocytic cells, MDM from normal donors were infected in vitro with the monocytotropic HIV-1Ba-L strain, in the presence or absence of LPS (1 μg/ml). Fig. 1 A shows that p24 Ag secretion in untreated MDM cultures rapidly reached high levels, which were maintained for over 10 d. In contrast, p24 Ag secretion by LPStreated MDM remained extremely low throughout the culture time. RT activity in the same cultures showed a similar pattern (data not shown). Fig. 1 B shows that LPSdependent inhibition of p24 Ag secretion was also observed in MDM cultures infected in vitro with HIV-15088, a primary isolate from an asymptomatic HIV-1-infected patient with the biological characteristics of an NSI isolate. LPS had a potent inhibitory effect on the replication of both HIV-1Ba-L and HIV-15088. Fig. 1 C shows that p24 Ag secretion was inhibited by >70% using LPS at a concentration of 1 ng/ml. Notably, inhibition was still apparent when LPS was added at 10 pg/ml, a physiologically significant concentration (13). Interestingly, LPS addition did not inhibit HIV-1 expression in MDM cultures infected with the SI laboratory strain, HIV-1IIIB (Fig. 1 D). The surprisingly high levels of replication of our HIV-1IIIB in MDM are likely to result from multiple passages of the viral stock in human primary PBMC. Addition of LPS did not result in significant cell death, nor in apoptosis, as assessed by Trypan blue or propidium iodide staining (data not shown).

Bottom Line: A combination of recombinant C-C chemokines blocked HIV-1 infection as effectively as LPS.Here, we report an inhibitory effect of C-C chemokines on HIV replication in primary macrophages.Our results raise the possibility that monocytes may play a dual role in HIV infection: while representing a reservoir for the virus, they may contribute to the containment of the infection by releasing factors that suppress HIV replication not only in monocytes but also in T lymphocytes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Technological Research, San Raffaele Scientific Institute, Milan, Italy.

ABSTRACT
Human immunodeficiency virus-1 (HIV-1) expression in monocyte-derived macrophages (MDM) infected in vitro is known to be inhibited by lipopolysaccharide (LPS). However, the mechanisms are incompletely understood. We show here that HIV-1 suppression is mediated by soluble factors released by MDM stimulated with physiologically significant concentrations of LPS. LPS-conditioned supernatants from MDM inhibited HIV-1 replication in both MDM and T cells. Depletion of C-C chemokines (RANTES, MIP-1 alpha, and MIP-1 beta) neutralized the ability of LPS-conditioned supernatants to inhibit HIV-1 replication in MDM. A combination of recombinant C-C chemokines blocked HIV-1 infection as effectively as LPS. Here, we report an inhibitory effect of C-C chemokines on HIV replication in primary macrophages. Our results raise the possibility that monocytes may play a dual role in HIV infection: while representing a reservoir for the virus, they may contribute to the containment of the infection by releasing factors that suppress HIV replication not only in monocytes but also in T lymphocytes.

Show MeSH
Related in: MedlinePlus